OK I am planning to start the L98 rebuild this week any advice on the initial break in / running time. I looked around and most people say do not run the engine at idle during the first start up, instead vary the RPM during the first start up time. What do you think? :hurray:

 

Yep, run dino oil and vary the rpm's... 2k rpm max i believe... for a few minutes. Then change oil.

 

first, Make sure you fill the oil filter first with oil,,,should take a pint+

OIl prime the motor
2a you can use an old distr or
2b I just unplugged my fuel pump fuse and cranked it till my oil pressure came up in th edash.

 

-Check out the tech tips, cross generation for an easy way to prime your oil system.
-Use dino oil (non-synthetic) for the first 1000 miles.
-You don't have to break in your cam since it's a roller cam.
-After you start it up and make sure your timing is correct and verify that there aren't any leaks or wierd noises, drive it for about 20 miles, but vary the engine speed and load that it sees. To do this, keep the tranny out of O.D., accelerate to 55, then, without applying the brake, let the speed drop to 35, then accelerate up to 55, then drop to 35. Do this for about 20 miles. This will ensure that your rings get seated properly.
-After your ring seating drive, change the oil and filter.
-During the first 500(ish) miles, try to avoid stop and go traffic, but also avoid long periods of cruising. You want to vary the engine load, but you don't want to be in heavy traffic either.
-Change your oil and filter again after 500 miles. Still try to take it easy on the engine, but you can do stop and go type of driving if you have to.
-After about 1000, you can change your oil to synthetic, and drive it like you stole it! :cheers:

 

Here's something to think about.
http://mototuneusa.com/break_in_secrets.htm

:cheers:

 

I had read that article before but it's a good read, worth the 5-10 minutes to read again for sure :thumbs:

 

Motomans breakin techniques sound good, but aren't as radical as he makes it sound. Motomans techniques aren't as much new as new to the general public. He is a bit more agressive than what I've seen before, but not a hwole bunch.

One of the reasons his techniques aren't recommended by manufactuerers to the general public is that if you don't pay attention to what he says and you overdo it, it's easy to do some damage.

Years ago I was amazed at just how short a break in engine manufatuerers recommend for engines run on dynos. The ones I remember were under one hour before pulling series of full throttle dyno runs. I saw factory engineers doing and recommending about the same on the dyno as Motoman recomends over 20 yearsa ago.

The reason you need to follow Motoman's instructions carefully if you use his method is that if you keep the power on too long, the high pressure on the rings he mentioned will create local hot spots and caouse things to not were in properly.

If Motomans instructions were in the owners manual on new cars, a lot of owners would interpret them to mean that they could drive their new car as hard as they wanted form the start without hurting it. The manufacturers instructions to take it easy for 500 or 1000 miles are harder to misinterpret.

Anyone contemplating doing a Motoman breakin should read his instructions sevral times, be sure they understand them, then follow them carefully and don't over do it on the length of early full throttle bursts. Also be sure to interspace the full throttle bursts that with a lot of off throttle slowdowns.

 

What's the reason not to use synthetic oil on start up? I am rebuilding the car so it is not street legal yet, should I try to do the initial break in in the garage ( the car is up on stands and can be put in to gear and run in all the gears (with out tires). :)

 

Synthetic oil actually does its job too well. It's so slippery it prevents the rings from breaking in. Dino oil provides the right amount of friction for breaking in. But no do not break in the engine without driving it. You need to exhibit some loading on the engine for the rings to seat properly. The above link is a good read on breaking in an engine. Good luck! :cheers: